Bug 57465

Summary: kldunload rtc.ko causes a panic; yet it's in rc.d script
Product: Ports & Packages Reporter: Jan Srzednicki <w>
Component: Individual Port(s)Assignee: silby
Status: Closed FIXED    
Severity: Affects Only Me    
Priority: Normal    
Version: Latest   
Hardware: Any   
OS: Any   

Description Jan Srzednicki 2003-10-01 17:50:17 UTC 
ports/emulators/rtc is a real time clock port, which is used by vmware
(and instaled as a dependency for a emulators/vmware3 port).

Along with the module, there comes a rc.d script, namely rtc.sh. It
loads the module on start and unloads it on stop.

The module however, is somewhat broken. After using vmware and
"kldunload rtc.ko" I get a panic. Well, I know kldunloading modules is
always tricky and I should not play with this when I don't have to, but
this kldunload is enabled by default via the port!

The rtc.ko also causes a panic after a reboot when it wasn't
kldunloaded, but this panic is not so severe, as the buffers are flushed
first and the filesystems are synced.

Fix: 

First of all, remove the kldunload thing from rc.d script
(ports/emulators/rtc/files/rtc.sh).

VMware says that rtc.ko is only needed for some windows stuff. As the
port is broken (at least on 5.1-R) and not so-needed, maybe it would be
better to remove the dependency (or make it an option, with a warning).

The best fix would be fixing the module itself, of course. ;)
How-To-Repeat: 
Install ports/emulators/rtc and ports/emulators/vmware3.

Configure a vmware guest system, turn it on, play with it, then turn off.

Reboot the system.
Comment 1 Philipp Mergenthaler 2003-10-02 09:24:41 UTC 
The bug is that the module, on unloading, calls destroy_dev() twice
for its device. Doing this causes a panic.

Fix:
--- ports/emulators/rtc/files/rtc.c_orig	Thu Oct  2 10:20:17 2003
+++ ports/emulators/rtc/files/rtc.c	Thu Oct  2 09:58:13 2003
@@ -168,7 +168,6 @@
 	if (sc->var.flags.opened) {
 		return EBUSY;
 	}
-	destroy_dev(sc->dev);
 	FREE(sc, M_DEVBUF);
 	return error;
 }
Comment 2 Peter Pentchev freebsd_committer freebsd_triage 2003-10-02 12:46:09 UTC 
Responsible Changed
From-To: freebsd-ports-bugs->freebsd-emulation

Over to the maintainer group.
Comment 3 Mikko Tyolajarvi 2003-10-02 16:45:19 UTC 
I ran into this some time ago, and found that you get different
results depending on whether the device has been opened or not.

Have you tried kldunloading "rtc" w/o using it first, e.g. directly
after boot?

I've been using the following patch for a while:

--- rtc.c.org   Wed Aug 20 20:41:50 2003
+++ rtc.c       Thu Oct  2 08:40:37 2003
@@ -299,7 +299,8 @@
                DLog(Lfail, "%p busy", sc);
                return error;
        }
-       destroy_dev(rtc_dev);
+       if (sc == NULL)
+               destroy_dev(rtc_dev);
 #if __FreeBSD_version < 500104
        error = cdevsw_remove(&rtc_cdevsw);
 #endif

Which seems to work find for me in all cases.  I made a mental note to
submit a PR once I've tested out the fix, and then of course, I forgot
all about it... :)

   $.02,
   /Mikko
Comment 4 Jan Srzednicki 2003-10-06 17:49:11 UTC 
On Thu, Oct 02, 2003 at 08:45:19AM -0700, Mikko Työläjärvi wrote:
> 
> I ran into this some time ago, and found that you get different
> results depending on whether the device has been opened or not.
> 
> Have you tried kldunloading "rtc" w/o using it first, e.g. directly
> after boot?
> 
> I've been using the following patch for a while:
[snip]
> Which seems to work find for me in all cases.  I made a mental note to
> submit a PR once I've tested out the fix, and then of course, I forgot
> all about it... :)

This patch doesn't work for me; kldunload rtc still causes a panic.

-- 
Jan 'Winfried' Srzednicki
w@expro.pl
Comment 5 Jan Srzednicki 2003-10-06 17:51:14 UTC 
On Thu, Oct 02, 2003 at 10:24:41AM +0200, Philipp Mergenthaler wrote:
> The bug is that the module, on unloading, calls destroy_dev() twice
> for its device. Doing this causes a panic.
> 
> Fix:
> --- ports/emulators/rtc/files/rtc.c_orig	Thu Oct  2 10:20:17 2003
> +++ ports/emulators/rtc/files/rtc.c	Thu Oct  2 09:58:13 2003
> @@ -168,7 +168,6 @@
>  	if (sc->var.flags.opened) {
>  		return EBUSY;
>  	}
> -	destroy_dev(sc->dev);
>  	FREE(sc, M_DEVBUF);
>  	return error;
>  }

This one seems to work fine. Thanks. ;)

-- 
Jan 'Winfried' Srzednicki
w@expro.pl
Comment 6 Gerald Pfeifer freebsd_committer freebsd_triage 2003-10-13 19:25:45 UTC 
Responsible Changed
From-To: freebsd-emulation->emulation

Change freebsd-emulation to emulation so that the list only receives 
one list of open PRs.
Comment 7 silby freebsd_committer freebsd_triage 2004-01-17 18:15:19 UTC 
Responsible Changed
From-To: emulation->silby

I will fix this and a bunch of other things in the rtc driver in the 
next week or two.
Comment 8 silby freebsd_committer freebsd_triage 2004-01-23 09:08:07 UTC 
State Changed
From-To: open->closed

Suggested fix committed.